Charles M. Balkcom, Jr. was tried and convicted of robbery and aggravated battery. In his sole enumeration of error, Balkcom claims that the trial court erred in allowing the state to attempt to impeach a witness for the defense by asking about criminal proceedings against two of her brothers, in order to show bias against the state. He has cited no authority in support of his position. “As a general rule, and particularly when the evidence is conflicting, a party may show any fact or circumstance that might affect the credit of an opposing witness. And on cross-examination it is always permissible to sift the motives of the witness and to show, if possible, any reason other than a purpose to tell the truth which may consciously or un*480consciously actuate him in his testimony.” (Citations and punctuation omitted.) Arnold v. State, 163 Ga. App. 10, 13 (4) (293 SE2d 501). (1982). This enumeration of error is without merit.

Judgment affirmed.